Herpes virus infections, though known, are difficult to treat because of the lack of effective drugs. An effective anti-herpes drug could be used in the treatment or prevention of herpes dermatitis, herpes genitalis, herpes keratitis, herpes encephalitis and as provided by the present invention, herpes simplex virus. Although herpes simplex is a very common, though minor disease, the only basic treatment presently available is the application of 5-iodo-2'-deoxuridine (idoxuridine).